Exercise helps protect people from colds, suggests a study published in the British Journal of Sports Medicine. During two 12-week periods in 2008, members of a cohort of 1,002 adults who said they exercised at least five days a week had 43 percent fewer days with a respiratory tract infection than those who just exercised one day a week or not at all. The severity of infections was reduced by as much as 41 percent in those who were highly fit, the researchers at Appalachian State University found.
Dr. Ross says this study seems well-designed, but worries about potential confounders. “I’m wondering, is it just possible that people who had more upper respiratory tract infections had less time to exercise? Could they be mixing up cause and effect?”
